This power control from a 1968 Motorola manual shows how to use a contemporary diac as a zero-crossing detector. The SCR is of the type depending on the power of the load.
Found in an old American publication, this circuit is intended for audio experiments. The...
This battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The...
This power supply for model railroad was found in a February 1961 Radio Electronics Magazine. The...